HANOI, Sept 10 (Reuters) - Strong growth in telephone and textile exports helped Vietnam post a $2.2 billion trade surplus in August, according to customs data released on Monday that completely confounded the government’s estimate of a $100 million deficit for the month.

The August surplus even surpassed Vietnam’s $2.1-billion surplus for all of last year, and was a positive signal for economic growth, which is expected to beat the government’s forecast of 6.7-percent target for 2018.

Exports in August rose 15.6 percent from a month earlier to $23.48 billion, while imports rose 1.6 percent to $21.28 billion, the customs department said on its website.

Exports in January-August rose 16.7 percent annually to $158.4 billion, led by shipments in smartphones, garments and electronic home appliances, and were on track to outperform the government’s full-year target for a 7-8 percent increase.

Vietnam, the largest producer of smartphones for Samsung Electronics, shipped $45 billion worth of telephones and spare parts in the eight-month period, up 32 percent annually, easily outstripping the government’s estimate of $30.9 billion, the report showed.

Textile, garments, electronic and computer exports also rose strongly in the first eight months with a combined value of $52 billion, also much higher than the government’s estimate of $37.9 billion, official data showed.

Exports of steel and ingots jumped 55 percent in the eight-month period to $3.1 billion, higher than the government’s estimate of $2.9 billion.

The United States has slapped steel import duties on steel products from Vietnam that originated in China, to deter Vietnam from being used for transhipment by China to avoid U.S. tariffs.